Receiving apparatus.



H. SHOBMAKER.

RECEIVING APPARATUS.

APPLICATION FILED 1101/13, 1909.

1,009,106. Patented Nov. 21, 1911.

2 BHBBTS SHEET 1.

:62. ATTORNEY.

fiWITNEZSfS: I INVENTOR 44 W 7 MEW I 6%- H. SHOEMAKER.

RECEIVING APPARATUS. APPLICATION FILEDJTOV. s, 1909.

1,009,106. Patented Nov.21,1911.

.2 SHEETS-SHEET 2.

i :INVEN TOR WITNESSES: BY 2 Z GM...) 8M 7 X2 W dTTORNEY.

UNITED STATES HARRY snom uxnn, onanasny 01172, NEW JERSEY.

' nncmvnie remains.

Tocll whom it may concern:

Be it known that I, HARRY SHOEMAKER,

a citizen of the United vStates, residing at Jersey City, county of Hudson, State of 'New Jersey, have invented-certain new and useful Improvements in Receiving Apparatus, of which the following is a specification.

My invention relates to telegraphic or telephonic receiving apparatus, and more particularly to the recelving apparatus employed in wireless telegraph or telephone systems in which the signals or messages are represented by electro-radiant energy transmitted threu h the natural media.

My invention reittes more particularly to. receiving apparatus which shall be selective of the energy transmitted to it and which is provided witliguarding means or apparatus for renderi g it indifierent to or immune from other energy simultaneously transmitted.

To this end I provide means for rendering the receiving apparatus proper selective to a greater or less degree, and associate with such receiving apparatus means which shall be selective, to a greater orless degree, of, other-energy or energies which may b e "transmitted simultaneously with the energy intended to bereceived by the receiving apparatus proper, and causing or. allowing such other undesired ener or energies to absorbed in paths or circuits other than the path or circuit including or associated with the receiving apparatus proper.

The undesired energy which may be simultaneously transmitted with the energy representing the signal or messa e which it is desired to receive, may be issipated in a guard path or circuit to which it is selected to produce heat or to be otherwise consumed or transformed. To this end I may, for example, provide in such path or circuit a resistance which shall consume the undeislired energy and transform the same into eat.

For the urpose of consuming or converting the un esired energy, I may use in place of a resistance any other suitable consumption or translating device. I

My invention resides in other features hereinafter described and claimed.

My invention resides also in the method of and apparatus for selectively receivin signals or messages as hereinafter describe Specification of Letters Patent. P t t d 21, 1911. Application filed November 8,},909. Serial 170. 585,894. I

.For an illustration of some of the forms which my improvedv receiving apparatus may take,

Figure 1- is adiagrammatic view illustrating receiving apparatus proper with which 15 associated, by the employment of a F1 and guarding apparatus both inductively associated with a common aerial conductor.

Fig. 4 is a diagrammatic view of a receiving apparatus inductively associated with an aerial conductorwith which is inductively related a plurality of guard paths or circuits. Fig. 5 is a diagrammatic view illustrating the employment of a looped aerial conductor, paths or circuit-s being inductively related with the loop while the receiver circuit proper is conductively associated therewith. Fi 6 is a diagrammatic view of apparatus similar to that shown in Fig. 5, except that the receiving apparatus proper is aplurality of guarding reference is to be had to the ac- .companymg drawings, in which:

also in inductive ,relation with the looped aerial conductor.

In Fig. 1, A represents the receiving antenna or aerial conductor of a wireless telegraph or'telephone station. Between the conductor A and earth G are serially connected the inductance L and the variable condenser K, having preferably an air dielectric. The inductance L may take the form of a coil of wire wound upon a cylinder of insulating material, or may take any other suitable form. As shown, a.vari-' able ortion of this inductance L is connected in series with the aerial conductor A and the condenser K. In shunt to the variable portion L'- of the inductance L is connected the variable condenser K. In shunt to the condenser K are connected the variable condenser K and the detector or wave-responsive device D, of any suitable type. Andin shunt to the detector D is connected a circuit including the telephone signa or messagesby the receiving appa-- '40 or closed oscillating instrument or other signal translating instrument T, it being understood that such local circuit will include a battery or other source of -energy when thetype of waveresponsive device or detector D requires it. By varying L and K, or either of them, the antenna circuit or path may have its natural eriod changed or varied between the limits or which it is suited or designed. By vary ing L and K or either of them, the local circuit may have its. natural period varied to correspond with the natural period ofv the antenna path or circuit. The mutual inductance of the antenna circuit and the circuit including L and K. may be varied, as by keeping L constant, but shifting its two contacts so as to change its geometrical relation with L. The condenser-K is 'ven such a value or adjusted to such a vail ie that current flows through the receiver circuit only when L and K are adjusted for resonance. 1

The apparatus as thus-far described constitutes a tuned or selective wireless telegraph or telephone receiving system. It is to e understood thatwmy invention is not limited to the receiving apparatus proper being constructed of the arts and arranged as shown, for it is re y understood that any other form or arrangement of selective receiving apparatusis comprehended by my invention.

. -A ssociated with the. receivin apparatus proper, as above described, is t e guarding apparatus for diverting from the receiving apparatus proper undesired energy which may betransmltted simultaneously with the ener which it is desired to interpret as ratus propera This guardmg apparatus comprises the antenna or aerial conductor A between which and the earth G is serially connected a variable'inductance L, a varireceived in the able resistance R and the variable condenser K. The condenser K may be short circuited by closing the switch 8. When the switch 8 is open the condenser K is in series ,in the antenna circuit or path and the effect is of inserting capacity in such path or'circuit so that the, natural period thereof shall be less than the natural period of the circuit or path when the capacity is not so inserted, as when theswitch 's is closed. Since this guarding circuit or path includes resistance as R, such path or circuit. has a eater dampening factor than the receiving apparatus proper, shown to the right of Fig. 1; that is to say, the undesired energy guarding circuit or path is converted into heat by dissipation in the resistance R. L and K, or either of them, may be adjusted soas to make the guarding circuit .or path'more or less selectiveoi the undesired energy. The inductance L may be of high resistance conductor so-that p10 ed.

a separate resistance R need not. be em-- uppose two transmitting stations are simultaneously sending out energy, the wave.

length ofthe one transmitting station which is communicating with the station at which the receiving apparatus of Fig. 1 is located,

- being 1, while the wave length transmitted by the other station is k. The receiving apparatus proper is then' attuned to a wave length 7., while the guarding apparatus is attune to the undesired frequency, that is, to a a wave length l. The energy having wave I length X will be received by the guard apparatus and dissipated into heat, or otherwise consumed or converted; at any rate, it is prevented irom affecting or controlling the receiving apparatus proper. hand, the energy having wave length will be received by the receiving ap aratus proper and will do useful work in aiibcting,

- actuating or controlling the wave-responsive On the other device or detector D, to reproduce signals or '1 messages in the manner well understood .in

the art.

The resistance R of the guard circuit or path should be of such magnitude or value as to make the guard circuit or path practically dead-beat, that is, the resistance should not be so great as to destroy entirely its oscillating properties, but should preferably be high enough to convert all of the energy of the oscillations corresponding to the wave length l as quickly as possible into heat. This preferred condition exists when the resistance R is equal to the where L is the inductance and K represents the efl'ective capacity.

In Fig. 1 separate and distinct antennae or-aerial conductors A and A are provided for the receiving apparatus proper and for the guard apparatus. In such case the distance between thelantennae or aerial conductors A and A should not be more. than one-quarter of thelen h of "the wave of the-energy against which it is desired to ard the receiving apparatus proper, so.

that the receiving apparatus proper andv the guard'apparatus shall not operate as separate and independent receiving apparatus with regard to the received. energy.

While in Fig. 1 onlyone guard circuit or path is shown, several guard circuits may be employed if desired.

Thus, Fig. 2 represents a guarded receiving apparatus with two guard circuits or paths, each suited for dissipating an undesired energy of given frequency or wave length. The arrangement is the same as in Fig. 1, except that now the same antenna is used for the guard apparatus as for the receiving apparatus proper. The. second messes guard circuit or path contains the variable mductance D an ad'ustable resistance R I and the variable con" enser K, which may be short circuited by the closure of the switch a. The path including the inductance U maybe attuned to an undesired frequency either'abo've or-b'elow the fre uency v the antenna circuit or path.

.understood that more of the energy desired to be receivedthe receiving apparatus proper. 'Andsimi arly, the guard path including the inductance L may be attunedto a frequency" either below or above the desired frequency It is-to be guard circuits may be associated, than shown in Fig. 2, and'attuned to still other frequencies. With these guard circuits or paths any energy represented by frequenciesabove'or below the frequency of the desired energy, isconverted spect to the antenna circuit or path and (includes the variable inductance L, variable condenser K and variable resistance R. It is preferred that the guard circuit including the resistance It should be closely coupled or in'close inductive relation with the antenna circuit or path, while the receiver circuit proper may be loosely coupled with In Fig. 4 the arrangement is similar to that shown in Fig. 3, except that a pluof guard circuits are inductively re with the antenna circuit or path. Here again, it is preferred that the guard circuits be closel coupled with respect to the antenna circuit or path, while the receiving circuit proper may be loosel coupled with the antenna circuit or path. These three guard circuits or paths are easily disralit lated tinguished as including respectively the variable resistances R, R and R variable inductances L, L and L and variable condensers K, K and K These guard circuits are attuned to the frequencies of the undesired energies. I

In Fig. 5 the aerial conductor A is in the form of a loop, the 100 being completed by a variable inductance l a connectionbeing made to earth G throu h the condenser K from a variable point a ong the inductance L. In shunt to a variable ortion of the inductance L is connected t e variable condenser K, in shunt with which is a variable condenser K and the detector D, as in the previous cases the detector D and the telephone or signal translating instrument T adj us'table resistance R condenser K. guard circuits may be employed or a greater number than shown may be employed and shown may be 'employe belonging to the receiving apparatus proper.

Here two guard circuits are shown in in} ductive relation with the' loop circuit or path, One of these guard circuits includes the variable inductance L, adjustable re- 'si'stanc'e R and variable condenser K. The

other comprises the variable inductance L,

Obviously, only one of these attuned for the purposes hereinbefore described.

Fig. 6 is similar to Fig. 5, except that the receiving apparatus proper is inductively related with respect to the loop path or circuit instead of conductively as in Fig. 5. Here again,moreor less (guard circuits than above indicated. Here again, the guard circuits are preferably closel cou led with respect to the loop circuit w ile t e receiving apparatus proper may be loosely coupled. And it is to be understood that when ever inductive couplings are employed the coupling may be made either loose or close.

at I claim is:

' 1. The combination with receiving apparatus, of guarding apparatus associated therewith, said guarding apparatus com prising means for selecting energy ofthe frequency of undesired ener y, and means .in said guarding apparatus or dissipating the selected energy and preventing sustained oscillations. e 2. The combination with receiving apparatus selective of energy of desired frequency, of associated guarding apparatus selective of undesired energy of a different frequency, and means in said guarding apparatus for dissipating the received undesired energy and preventing sustained oscillations.

3. The combination with apparatus for receiving high frequency electro-radiant enand the adjustable for the purposes 7 ergy, of guarding apparatus therefor comprising means for selecting energy of undesired frequency, and a resistance sufiicient to prevent persistent oscillations in said selecting means.

4. The combination with receiving apparatus, of guarding apparatus comprising means for selecting energy of undesired freuency, and a dissipative resistance, said issipativ'e resistance being of a value for rendering said guard apparatus almost dead-beat.

5. The combination with a selective receiving apparatus, of a plurality of associated guarding apparatus, each guarding apparatus diverting from said receiving apparatus energy of undesired frequency, each guarding apparatus being selective of energy of afrequency different from the frequency of which every other is selective, and

means associated with guarding apparatus v for dissipating the enter selected thereby and for preventing persistent oscil-' ductor.

13. In combination, an aerial conductor, receiving apparatus associated therewith, means for tuning said receiving apparatus to a desired frequency, and a guarding path lations. t

6. The combination with receiving apparatus, of guarding apparatus associated therewith, said guarding apparatus comprising a closed circuit selective of energy of undeslred frequency, and means in said closed circuit preventing persistent oscillations." 7. The combination with a selective receiving apparatus, of guarding apparatus associated therewith, said guarding appa-- ratus comprising a closed circuit selective of energy of undesired frequency and means in said closed circuit'giving to said circuit a dampening factor greater than the dampening factor of said receiving apparatus.

8. In combination, receiving apparatus.

comprising a tuned path,iand associated guarding apparatus comprising a tuned path having a greater dampening factor than said first mentioned tuned path.

9. In combination, receiving apparatus,

comprising a path tuned to energy .of desired frequency, associated guarding apparatus comprising a path tuned to energy of undesired frequency, the tuned path of the guarding apparatus having a greater dampenmg actor than the tuned path of'said receiving apparatus.

10. In combination, an aerial conductor,

- and a receiving circuit associated therewith,

means ,fortuning said receiving circult to desired energy, an associated antenna, and means tunedto a different frequency associated therewith.

11. In combination, an aerial conductor, and a receiving circuit associated therewith, means for tuning said receiving circuit to desired energy, an associated antenna, and means tuned to a different frequency associated therewith and including energy dissipating means.

12. In combination, an aerial conductor,

a and a receiving circuit associated therewith,

means for tuning said receiving circuit to desired energy, and a second aerial conductor, tuning means having a greater .dampemng factor than the recelving'apparatus associated with said second aerial coitin inductive relation with respect to said antenna and tuned to a different frequency, said guarding path including energy d1ss1- vpating means preventing sustained oscillations. 7

14. The combination with an antenna, of receiving apparatus associated therewlth,

means for tuning said receiving apparatus to desired frequency, and a plurality of guarding paths ininductive relation with said antenna, each guardin path tuned to a different frequency, an each having a greater dampening factor than .said receiving apparatus. I 1

15. The combination with a looped aerial conductor, of receiving apparatus associated therewith, means for tuning said receiving apparatus to' energy of desired frequency, and a guard path associated with said looped aerial cond'uctorand tuned to a different frequency, the dampening factor of said guard path'being' greater than that of V the receiving. apparatus.

16. The combination with a looped aerial conductor, of receiving apparatus associated therewith, means for tuning said receiving apparatus to energy of desired frequency,

and a guard path associated with said looped aerial conductor and tuned to a dif-. ferent frequency, the dampening factor of HARRY SHOEMAKER. Witnesses:

Fnnolr W. Mmcmr, A. Ronnn'rs SHARPLES.

said guard path being greaterthan that of the receiving apparatus, said guard path 

